removed extract_files and read_json files from views

11 files changed, 345 insertions, 138 deletions

diff --git a/yaksh/admin.py b/yaksh/admin.py
index 2ce3ac4..4ef2f3d 100644
--- a/yaksh/admin.py
+++ b/yaksh/admin.py
@@ -1,10 +1,13 @@
 from yaksh.models import Question, Quiz
 from yaksh.models import TestCase, StandardTestCase, StdoutBasedTestCase, Course
+from yaksh.models import Question, Quiz, Course, QuestionPaper
+from yaksh.models import TestCase, StandardTestCase, StdoutBasedTestCase
 from django.contrib import admin
 
 admin.site.register(Question)
 admin.site.register(TestCase)
 admin.site.register(StandardTestCase)
 admin.site.register(StdoutBasedTestCase)
-admin.site.register(Quiz)
 admin.site.register(Course)
+admin.site.register(Quiz)
+admin.site.register(QuestionPaper)
diff --git a/yaksh/documentation/installation.rst b/yaksh/documentation/installation.rst
index 4acee61..51efea7 100644
--- a/yaksh/documentation/installation.rst
+++ b/yaksh/documentation/installation.rst
@@ -64,4 +64,52 @@ This starts the code server
 
 **And entering the following admin credentials**
 	* Username: admin
-	* Password: admin
\ No newline at end of file
+	* Password: admin
+
+Running The Code Server
+-----------------------
+
+**Local Instance**:
+
+In a new terminal run the command::
+
+	sudo python /path/to/code_server.py
+
+Keep this instance running in the background
+
+**Using Docker**:
+
+1. Install docker 
+
+2. Create a Docker Image using the Docker file:
+
+	* Go to the directory where the project is located::
+
+		cd /path/to/online_test
+
+	* Build a docker image using the Dockerfile::
+
+		sudo docker build --tag=yaksh_code_server:v1 .
+
+3. Start a Docker container::
+
+		docker run -d -p 8001:8001 -p 53579:53579 -v /path/to/online_test/yaksh/output:/src/yaksh/output yaksh_code_server:v1
+
+**Note**:
+	* The default ports on which the code server runs and the pool port on which the former ports are available is specified in online_test/yaksh/settings.py. The code server also supports multiple ports
+
+	* The server port is 8001 by default, this can be changed in the settings::
+	
+		SERVER_PORTS = 8001
+
+	* Multiple ports can be specified as::
+	
+		SERVER_PORTS = [8001, 8002, 8003, 8004, 8005] # Or use range(8001, 8040) for larger number of ports
+
+	* The default pool port is 53579 by default, this can be changed in the settings::
+	
+		SERVER_POOL_PORT = 53579
+
+	* The docker command to start a docker container when using multiple ports is::
+	
+		docker run -d -p 8001-8039:8001-8039 -p 53579:53579 yaksh_code_server:v1
diff --git a/yaksh/file_utils.py b/yaksh/file_utils.py
index 8f6f6e5..afcf9e8 100644
--- a/yaksh/file_utils.py
+++ b/yaksh/file_utils.py
@@ -13,12 +13,10 @@ def copy_files(file_paths):
         file_name = os.path.basename(file_path)
         files.append(file_name)
         shutil.copy(file_path, os.getcwd())
-        if extract and zipfile.is_zipfile(file_name):
-            unzip = zipfile.ZipFile(file_name)
-            for zip_files in unzip.namelist():
-                files.append(zip_files)
-            unzip.extractall()
-            unzip.close()
+        if extract:
+            z_files = extract_files(file_name)
+            for file in z_files:
+                files.append(file)
     return files
 
 
@@ -31,3 +29,15 @@ def delete_files(files):
                 os.remove(file)
             else:
                 shutil.rmtree(file)
+
+
+def extract_files(zip_file):
+    zfiles = []
+    if zipfile.is_zipfile(zip_file):
+        zip_file = zipfile.ZipFile(zip_file, 'r')
+        for z_file in zip_file.namelist():
+            zfiles.append(z_file)
+        zip_file.extractall()
+        zip_file.close()
+        return zfiles
+
diff --git a/yaksh/models.py b/yaksh/models.py
index 5bb44fa..e296524 100644
--- a/yaksh/models.py
+++ b/yaksh/models.py
@@ -16,6 +16,7 @@ import pytz
 import os
 import shutil
 import zipfile
+import tempfile
 
 
 languages = (
@@ -292,7 +293,7 @@ class Question(models.Model):
         files_list = []
         for f in files:
             zip_file.write(f.file.path, (os.path.basename(f.file.path)))
-            files_list = os.path.basename(f.file.path)
+            files_list.append(os.path.basename(f.file.path))
         return files_list
 
     def _add_files_to_db(self, file_names):
@@ -305,11 +306,13 @@ class Question(models.Model):
 
     def _add_json_to_zip(self, zip_file, q_dict):
         json_data = json.dumps(q_dict, indent=2)
-        with open("questions_dump.json", "w") as json_file:
+        tmp_file_path = tempfile.mkdtemp()
+        json_path = os.path.join(tmp_file_path, "questions_dump.json")
+        with open(json_path, "w") as json_file:
             json_file.write(json_data)
-        zip_file.write(json_file.name)
+        zip_file.write(json_path, os.path.basename(json_path))
         zip_file.close()
-        os.remove(json_file.name)
+        shutil.rmtree(tmp_file_path)
 
     def __unicode__(self):
         return self.summary
@@ -603,7 +606,9 @@ class QuestionPaper(models.Model):
         if self.quiz.has_prerequisite():
             prerequisite = self._get_prequisite_paper()
             return prerequisite._is_questionpaper_passed(user)
-
+    
+    def __unicode__(self):
+        return "Question Paper for " + self.quiz.description
 
 ###############################################################################
 class QuestionSet(models.Model):
@@ -817,21 +822,28 @@ class AnswerPaper(models.Model):
             Adds the completed question to the list of answered
             questions and returns the next question.
         """
+        next_question = self.next_question(question_id)
         self.questions_answered.add(question_id)
         self.questions_unanswered.remove(question_id)
+        if next_question.id == int(question_id):
+            return None
+        return next_question
 
-        return self.current_question()
-
-    def skip(self, question_id):
+    def next_question(self, question_id):
         """
             Skips the current question and returns the next sequentially
              available question.
         """
-        questions = self.questions_unanswered.all()
-        question_cycle = cycle(questions)
-        for question in question_cycle:
-            if question.id==int(question_id):
-                return question_cycle.next()
+        unanswered_questions = self.questions_unanswered.all()
+        questions = list(unanswered_questions.values_list('id', flat=True))
+        if len(questions) == 0:
+            return None
+        try:
+            index =  questions.index(int(question_id))
+            next_id = questions[index+1]
+        except (ValueError, IndexError):
+            next_id = questions[0]
+        return unanswered_questions.get(id=next_id)
 
     def time_left(self):
         """Return the time remaining for the user in seconds."""
diff --git a/yaksh/templates/yaksh/addteacher.html b/yaksh/templates/yaksh/addteacher.html
index 7e04f71..6722a52 100644
--- a/yaksh/templates/yaksh/addteacher.html
+++ b/yaksh/templates/yaksh/addteacher.html
@@ -18,6 +18,7 @@
 		<button class="btn" type="button" name="button" onClick='location.replace("{{URL_ROOT}}/exam/manage/courses");'>Cancel</button> </center></form>
 </div>
 <br><br>
+
 <form action="{{ URL_ROOT }}/exam/manage/addteacher/{{ course.id }}/" method="post">
 {% csrf_token %}
 {% if success == True %}
@@ -56,8 +57,7 @@
 </form>
 {% if status == True %}
 <div class="row">
-    <div class="span6 offset4 wrap">
-        <center><b><u>Teacher(s) Added</u></b></center><br>
+    <div class="span6 offset4 wrap">  
         {% if teachers_added %}
         {% for teacher in teachers_added %}
         <div class="well">
diff --git a/yaksh/templates/yaksh/courses.html b/yaksh/templates/yaksh/courses.html
index 910a68d..4852d25 100644
--- a/yaksh/templates/yaksh/courses.html
+++ b/yaksh/templates/yaksh/courses.html
@@ -9,11 +9,11 @@
 {% endblock %}
 
 {% block manage %}
-<a href="{{URL_ROOT}}/exam/manage/allotted_course/">View Allotted Courses</a><br>
+
 {% if not courses %}
-    <center><h4> No new Courses added </h4></center>
+    <center><h4> No new Courses created </h4></center>
 {% else %}
-<center><h3> Course(s) Added</h3></center>
+<center><h3> Course(s) Created</h3></center>
     {% for course in courses %}
     {% if user != course.creator and course.name != "Demo_course"%}
         <h4> {{course.creator.get_full_name}} added you to this course</h4>
@@ -82,7 +82,76 @@
     </div>
     <br><br>
     {% endfor %}
-    <button class="btn primary" type="button" onClick='location.replace("{{URL_ROOT}}/exam/manage/add_course");'>Add New Course</button>
-    <button class="btn primary" type="button" onClick='location.replace("{{URL_ROOT}}/exam/manage/addquiz");'>Add New Quiz</button>
+    {% endif %}
+
+{% if allotted_courses %}
+    <center><h3> Course(s) Allotted </h3></center>
+
+    {% for course in allotted_courses %}
+        <div class="row show-grid">
+        <div class="span14">
+            <div class="row">
+                <div class="span6">
+                    <p>
+                        <b><u>Course</u></b>
+                        {% if course.active %}
+                            <span class="label success">Active</span>
+                        {% else %}
+                            <span class="label important">Closed</span>
+                        {% endif %}
+                    </p>
+                    <a href="{{URL_ROOT}}/exam/manage/course_detail/{{course.id}}/">{{ course.name }}</a>
+                    </br></br>
+                    <div class="row">
+                        <div class="span6 wrap">
+                            <center><b><u> Course Creator</u></b></center>
+                            {{course.creator}}
+                            <center><b><u>Teacher(s) Added to {{ course }}</u></b></center>
+                            {% if course.get_teachers %}
+                            <div align="left">
+                            <form action="{{URL_ROOT}}/exam/manage/remove_teachers/{{ course.id }}/" method="post">
+                            {% csrf_token %}
+                            {% for teacher in course.get_teachers %}
+                            <div class="well">
+                                <div class="row">
+                                    <div class="span3" style="width: auto;">
+                                        <input type="checkbox" name="remove" value="{{ teacher.id }}">&nbsp;{{ teacher.get_full_name }}
+                                    </div>
+                                </div>
+                            </div>
+                            {% endfor %}
+                            <button class="btn success" type="submit">Remove Selected</button>
+                            </div>
+                            {% else %}
+                            <center><b>No Teacher(s) Added</b></center>
+                            {% endif %}
+                            </form>
+                        </div>
+                    </div>
+                </div>
+                <div class="span6">
+                    <p><b><a href="{{URL_ROOT}}/exam/manage/searchteacher/{{course.id}}/">Add Teacher</a></b></p>
+                </div>
+                <div class="span6">
+                    <p><b><u>Quiz(zes)</u></b></p>
+                    {% if course.get_quizzes %}
+                        {% for quiz in course.get_quizzes %}
+                            <a href="{{URL_ROOT}}/exam/manage/addquiz/{{quiz.id}}/">{{ quiz.description }}</a><br>
+                    {% endfor %}
+                    {% else %}
+                        <p><b>No quiz </b></p>
+                    {% endif %}
+                </div>
+            </div>
+        </div>
+    </div>
+    <br><br>
+    {% endfor %}
+{% else %}
+    <center><h4> No new Courses allotted </h4></center>
 {% endif %}
+<button class="btn primary" type="button" onClick='location.replace("{{URL_ROOT}}/exam/manage/add_course");'>Add New Course</button>
+    {% if courses or allotted_courses %}
+    <button class="btn primary" type="button" onClick='location.replace("{{URL_ROOT}}/exam/manage/addquiz");'>Add New Quiz</button>
+{% endif %}    
 {% endblock %}
diff --git a/yaksh/templates/yaksh/question.html b/yaksh/templates/yaksh/question.html
index 73d851a..9a0f899 100644
--- a/yaksh/templates/yaksh/question.html
+++ b/yaksh/templates/yaksh/question.html
@@ -85,19 +85,6 @@ function call_skip(url)
     form.action = url
     form.submit();
 }
-    {% if error_message == 'Correct Output'%}
-	{% if paper.questions_left  %}
-	window.setTimeout(function()
-	{   
-        location.href="{{ URL_ROOT }}/exam/{{ paper.current_question.id }}/check/{{ paper.attempt_number }}/{{ paper.question_paper.id }}/"
-	}, 2000);
-	{% else %}
-	window.setTimeout(function()
-	{   
-		location.href="{{ URL_ROOT }}/exam/{{ question.id }}/check/{{ paper.attempt_number }}/{{ paper.question_paper.id }}/"
-	}, 2000);
-    {% endif %}
-	{% endif %}
 </script>
 
 {% endblock script %}
@@ -165,11 +152,17 @@ function call_skip(url)
          <input type=hidden name="question_id" id="question_id" value={{ question.id }}></input>
 
          {% if question.type == "mcq" %}
+        {% if error_message %}
+            <p>{{ error_message }}</p>
+        {% endif %}
          {% for test_case in test_cases %}
          <input name="answer" type="radio" value="{{ test_case.options }}" />{{ test_case.options }} <br/>
          {% endfor %}
          {% endif %}
          {% if question.type == "mcc" %}
+        {% if error_message %}
+            <p>{{ error_message }}</p>
+        {% endif %}
          {% for test_case in test_cases %}
          <input name="answer" type="checkbox" value="{{ test_case.options }}"> {{ test_case.options }}
          <br>
@@ -188,7 +181,7 @@ function call_skip(url)
 
          {% endif %}
  
-         {% if question.type == "mcq" or question.type == "mcc "%}
+         {% if question.type == "mcq" or question.type == "mcc"%}
          <br><button class="btn" type="submit" name="check" id="check">Submit Answer</button>&nbsp;&nbsp;
          {% elif question.type == "upload" %}
          <br><button class="btn" type="submit" name="check" id="check" onClick="return validate();">Upload</button>&nbsp;&nbsp;
diff --git a/yaksh/templates/yaksh/user_data.html b/yaksh/templates/yaksh/user_data.html
index 04544f9..2e7db50 100644
--- a/yaksh/templates/yaksh/user_data.html
+++ b/yaksh/templates/yaksh/user_data.html
@@ -56,11 +56,15 @@ User IP address: {{ paper.user_ip }}
 </p>
 <p>Student answer: {{ answers.0 }}</p>
 {% else %}{# non-mcq questions #}
-<pre> 
-{% for answer in answers %}################################################################################
+{% for answer in answers %}
+{% if not answer.skipped %}
+<pre>
+###############################################################################
 {{ answer.answer.strip }}
 # Autocheck: {{ answer.error }}
-{% endfor %}</pre>
+</pre>
+{% endif %}
+{% endfor %}
 {% endif %}
 {% with answers|last as answer %}
 <p><em>Marks: {{answer.marks}} </em> </p>
diff --git a/yaksh/test_models.py b/yaksh/test_models.py
index 1716c73..5c34e8e 100644
--- a/yaksh/test_models.py
+++ b/yaksh/test_models.py
@@ -11,7 +11,7 @@ from django.core.files import File
 import zipfile
 import os
 import shutil
-
+import tempfile
 
 def setUpModule():
     # create user profile
@@ -62,6 +62,14 @@ def tearDownModule():
     User.objects.all().delete()
     Question.objects.all().delete()
     Quiz.objects.all().delete()
+    dir_path1 = os.path.join(os.getcwd(), "yaksh", "data","question_25")
+    dir_path2 = os.path.join(os.getcwd(), "yaksh", "data","question_22")
+    dir_path3 = os.path.join(os.getcwd(), "yaksh", "data","question_24")
+    dir_path4 = os.path.join(os.getcwd(), "yaksh", "data","question_27")
+    shutil.rmtree(dir_path1)
+    shutil.rmtree(dir_path2)
+    shutil.rmtree(dir_path3)
+    #shutil.rmtree(dir_path4)
 
 
 ###############################################################################
@@ -109,8 +117,21 @@ class QuestionTestCases(unittest.TestCase):
             user=self.user2
         )
         self.question2.save()
+
+        # create a temp directory and add files for loading questions test
         file_path = os.path.join(os.getcwd(), "yaksh", "test.txt")
-        shutil.copy(file_path, "/tmp/")
+        self.load_tmp_path = tempfile.mkdtemp()
+        shutil.copy(file_path, self.load_tmp_path)
+        file1 = os.path.join(self.load_tmp_path, "test.txt")
+
+        # create a temp directory and add files for dumping questions test
+        self.dump_tmp_path = tempfile.mkdtemp()
+        shutil.copy(file_path, self.dump_tmp_path)
+        file2 = os.path.join(self.dump_tmp_path, "test.txt")
+        file = open(file2, "r")
+        django_file = File(file)
+        file = FileUpload.objects.create(file=django_file, question=self.question2)
+
         self.question1.tags.add('python', 'function')
         self.assertion_testcase = StandardTestCase(question=self.question1,
             test_case='assert myfunc(12, 13) == 15'
@@ -127,10 +148,14 @@ class QuestionTestCases(unittest.TestCase):
                            "language": "Python", "type": "Code",
                            "test_case_type": "standardtestcase",
                            "testcase": self.test_case_upload_data,
-                           "files": ['/tmp/test.txt'],
+                           "files": [file1],
                            "summary": "Json Demo"}]
         self.json_questions_data = json.dumps(questions_data)
 
+    def tearDown(self):
+        shutil.rmtree(self.load_tmp_path)
+        shutil.rmtree(self.dump_tmp_path)
+
     def test_question(self):
         """ Test question """
         self.assertEqual(self.question1.summary, 'Demo question')
@@ -145,15 +170,17 @@ class QuestionTestCases(unittest.TestCase):
                     tag_list.append(tag.name)
         self.assertEqual(tag_list, ['python', 'function'])
 
-    def test_dump_questions_into_json(self):
+    def test_dump_questions(self):
         """ Test dump questions into json """
         question = Question()
         question_id = [self.question2.id]
         questions_zip = question.dump_questions(question_id, self.user2)
+        que_file = FileUpload.objects.get(question=self.question2.id)
         zip_file = zipfile.ZipFile(questions_zip, "r")
-        zip_file.extractall("/tmp/")
+        tmp_path = tempfile.mkdtemp()
+        zip_file.extractall(tmp_path)
         test_case = self.question2.get_test_cases()
-        with open("/tmp/questions_dump.json", "r") as f:
+        with open("{0}/questions_dump.json".format(tmp_path), "r") as f:
             questions = json.loads(f.read())
             for q in questions:
                 self.assertEqual(self.question2.summary, q['summary'])
@@ -164,14 +191,13 @@ class QuestionTestCases(unittest.TestCase):
                 self.assertTrue(self.question2.active)
                 self.assertEqual(self.question2.snippet, q['snippet'])
                 self.assertEqual(self.question2.test_case_type, q['test_case_type'])
+                self.assertEqual(os.path.basename(que_file.file.path), q['files'][0])
                 self.assertEqual([case.get_field_value() for case in test_case], q['testcase'])
         for file in zip_file.namelist():
-            os.remove(os.path.join("/tmp/", file))
+            os.remove(os.path.join(tmp_path, file))
 
-    def test_load_questions_from_json(self):
+    def test_load_questions(self):
         """ Test load questions into database from json """
-        f_path = os.path.join(os.getcwd(), "yaksh", "data",
-                              "question_25", "tmp", "test.txt")
         question = Question()
         result = question.load_questions(self.json_questions_data, self.user1)
         question_data = Question.objects.get(pk=25)
@@ -187,8 +213,6 @@ class QuestionTestCases(unittest.TestCase):
         self.assertEqual(question_data.test_case_type, 'standardtestcase')
         self.assertEqual(os.path.basename(file.file.path), "test.txt")
         self.assertEqual([case.get_field_value() for case in test_case], self.test_case_upload_data)
-        rm_dir = os.path.dirname(os.path.dirname(f_path))
-        shutil.rmtree(rm_dir)
 
 
 ###############################################################################
@@ -442,7 +466,7 @@ class AnswerPaperTestCases(unittest.TestCase):
         self.answerpaper.save()
         # answers for the Answer Paper
         self.answer_right = Answer(question=Question.objects.get(id=1),
-            answer="Demo answer", 
+            answer="Demo answer",
             correct=True, marks=1
         )
         self.answer_wrong = Answer(question=Question.objects.get(id=2),
@@ -476,20 +500,85 @@ class AnswerPaperTestCases(unittest.TestCase):
         # Test completed_question() method of Answer Paper
         question = self.answerpaper.completed_question(1)
         self.assertEqual(self.answerpaper.questions_left(), 2)
-        # Test skip() method of Answer Paper
+
+        # Test next_question() method of Answer Paper
         current_question = self.answerpaper.current_question()
         self.assertEqual(current_question.id, 2)
-        next_question_id = self.answerpaper.skip(current_question.id)
+
+        # When
+        next_question_id = self.answerpaper.next_question(current_question.id)
+
+        # Then
         self.assertTrue(next_question_id is not None)
         self.assertEqual(next_question_id.id, 3)
+
+        # Given, here question is already answered
+        current_question_id = 1
+
+        # When
+        next_question_id = self.answerpaper.next_question(current_question_id)
+
+        # Then
+        self.assertTrue(next_question_id is not None)
+        self.assertEqual(next_question_id.id, 2)
+
+        # Given, wrong question id
+        current_question_id = 12
+
+        # When
+        next_question_id = self.answerpaper.next_question(current_question_id)
+
+        # Then
+        self.assertTrue(next_question_id is not None)
+        self.assertEqual(next_question_id.id, 2)
+
+        # Given, last question in the list
+        current_question_id = 3
+
+        # When
+        next_question_id = self.answerpaper.next_question(current_question_id)
+
+        # Then
+        self.assertTrue(next_question_id is not None)
+        self.assertEqual(next_question_id.id, 2)
+
+        # Test get_questions_answered() method
+        # When
         questions_answered = self.answerpaper.get_questions_answered()
+
+        # Then
         self.assertEqual(questions_answered.count(), 1)
         self.assertSequenceEqual(questions_answered, [self.questions[0]])
+
+        # When
         questions_unanswered = self.answerpaper.get_questions_unanswered()
+
+        # Then
         self.assertEqual(questions_unanswered.count(), 2)
         self.assertSequenceEqual(questions_unanswered,
                                  [self.questions[1], self.questions[2]])
 
+        # Test completed_question and next_question
+        # When all questions are answered
+        current_question = self.answerpaper.completed_question(2)
+
+        # Then
+        self.assertEqual(self.answerpaper.questions_left(), 1)
+        self.assertEqual(current_question.id, 3)
+
+        # When
+        current_question = self.answerpaper.completed_question(3)
+
+        # Then
+        self.assertEqual(self.answerpaper.questions_left(), 0)
+        self.assertTrue(current_question is None)
+
+        # When
+        next_question_id = self.answerpaper.next_question(current_question_id)
+
+        # Then
+        self.assertTrue(next_question_id is None)
+
     def test_update_marks(self):
         """ Test update_marks method of AnswerPaper"""
         self.answerpaper.update_marks('inprogress')
@@ -602,7 +691,7 @@ class CourseTestCases(unittest.TestCase):
     def test_add_teachers(self):
         """ Test to add teachers to a course"""
         self.course.add_teachers(self.student1, self.student2)
-        self.assertSequenceEqual(self.course.get_teachers(), 
+        self.assertSequenceEqual(self.course.get_teachers(),
                                      [self.student1, self.student2])
 
     def test_remove_teachers(self):
@@ -634,23 +723,23 @@ class CourseTestCases(unittest.TestCase):
 class TestCaseTestCases(unittest.TestCase):
     def setUp(self):
         self.user = User.objects.get(pk=1)
-        self.question1 = Question(summary='Demo question 1', 
+        self.question1 = Question(summary='Demo question 1',
             language='Python',
-            type='Code', 
+            type='Code',
             active=True,
-            description='Write a function', 
+            description='Write a function',
             points=1.0,
-            test_case_type="standardtestcase", 
+            test_case_type="standardtestcase",
             user=self.user,
             snippet='def myfunc()'
         )
-        self.question2 = Question(summary='Demo question 2', 
+        self.question2 = Question(summary='Demo question 2',
              language='Python',
-             type='Code', 
+             type='Code',
              active=True,
-             description='Write to standard output', 
+             description='Write to standard output',
              points=1.0,
-             test_case_type="stdoutbasedtestcase", 
+             test_case_type="stdoutbasedtestcase",
              user=self.user,
              snippet='def myfunc()'
         )
@@ -676,13 +765,13 @@ class TestCaseTestCases(unittest.TestCase):
     def test_assertion_testcase(self):
         """ Test question """
         self.assertEqual(self.assertion_testcase.question, self.question1)
-        self.assertEqual(self.assertion_testcase.test_case, 
+        self.assertEqual(self.assertion_testcase.test_case,
                              'assert myfunc(12, 13) == 15')
 
     def test_stdout_based_testcase(self):
         """ Test question """
         self.assertEqual(self.stdout_based_testcase.question, self.question2)
-        self.assertEqual(self.stdout_based_testcase.expected_output, 
+        self.assertEqual(self.stdout_based_testcase.expected_output,
             'Hello World'
         )
 
diff --git a/yaksh/urls.py b/yaksh/urls.py
index cd97dd4..d14ed1d 100644
--- a/yaksh/urls.py
+++ b/yaksh/urls.py
@@ -97,7 +97,6 @@ urlpatterns += [
         views.reject, {'was_enrolled': True}),
     url(r'^manage/searchteacher/(?P<course_id>\d+)/$', views.search_teacher),
     url(r'^manage/addteacher/(?P<course_id>\d+)/$', views.add_teacher, name='add_teacher'),
-    url(r'^manage/allotted_course/$', views.allotted_courses),
     url(r'^manage/remove_teachers/(?P<course_id>\d+)/$', views.remove_teachers, name='remove_teacher'),
     url(r'^manage/download_questions/$', views.show_all_questions),
     url(r'^manage/upload_questions/$', views.show_all_questions),
diff --git a/yaksh/views.py b/yaksh/views.py
index 616c3cc..bfa36fd 100644
--- a/yaksh/views.py
+++ b/yaksh/views.py
@@ -35,6 +35,7 @@ from yaksh.forms import UserRegisterForm, UserLoginForm, QuizForm,\
 from yaksh.xmlrpc_clients import code_server
 from settings import URL_ROOT
 from yaksh.models import AssignmentUpload
+from file_utils import extract_files
 
 # The directory where user data can be saved.
 OUTPUT_DIR = abspath(join(dirname(__file__), 'output'))
@@ -83,21 +84,6 @@ def add_to_group(users):
             user.groups.add(group)
 
 
-def extract_files(questions_file):
-    if zipfile.is_zipfile(questions_file):
-        zip_file = zipfile.ZipFile(questions_file, 'r')
-        zip_file.extractall()
-
-
-def read_json(json_file, user):
-    question = Question()
-    if os.path.exists(json_file):
-        with open(json_file, 'r') as q_file:
-            questions_list = q_file.read()
-            question.load_questions(questions_list, user)
-            os.remove(json_file)
-
-
 def index(request):
     """The start page.
     """
@@ -472,16 +458,22 @@ def skip(request, q_id, next_q=None, attempt_num=None, questionpaper_id=None):
     paper = get_object_or_404(AnswerPaper, user=request.user, attempt_number=attempt_num,
             question_paper=questionpaper_id)
     question = get_object_or_404(Question, pk=q_id)
+    if question in paper.questions_answered.all():
+        next_q = paper.next_question(q_id)
+        return show_question(request, next_q, paper)
+
     if request.method == 'POST' and question.type == 'code':
         user_code = request.POST.get('answer')
         new_answer = Answer(question=question, answer=user_code,
                             correct=False, skipped=True)
         new_answer.save()
         paper.answers.add(new_answer)
-    if next_q is None:
-        next_q = paper.skip(q_id) if paper.skip(q_id) else question
-    else:
+    if next_q is not None:
         next_q = get_object_or_404(Question, pk=next_q)
+        if next_q not in paper.questions_unanswered.all():
+            return show_question(request, question,  paper)
+    else:
+        next_q = paper.next_question(q_id)
     return show_question(request, next_q, paper)
 
 
@@ -493,7 +485,7 @@ def check(request, q_id, attempt_num=None, questionpaper_id=None):
             question_paper=questionpaper_id)
     question = get_object_or_404(Question, pk=q_id)
     if question in paper.questions_answered.all():
-        next_q = paper.skip(q_id)
+        next_q = paper.next_question(q_id)
         return show_question(request, next_q, paper)
 
     if request.method == 'POST':
@@ -522,7 +514,9 @@ def check(request, q_id, attempt_num=None, questionpaper_id=None):
                             correct=False)
         new_answer.save()
         paper.answers.add(new_answer)
-
+        if not user_answer:
+            msg = "Please submit a valid option or code"
+            return show_question(request, question, paper, msg)
         # If we were not skipped, we were asked to check.  For any non-mcq
         # questions, we obtain the results via XML-RPC with the code executed
         # safely in a separate process (the code_server.py) running as nobody.
@@ -543,17 +537,8 @@ def check(request, q_id, attempt_num=None, questionpaper_id=None):
             new_answer.save()
             return show_question(request, question, paper, result.get('error'))
         else:
-            # Display the same question if user_answer is None
-            if not user_answer:
-                msg = "Please submit a valid option or code"
-                return show_question(request, question, paper, msg)
-            elif question.type == 'code' and user_answer:
-                msg = "Correct Output"
-                paper.completed_question(question.id)
-                return show_question(request, question, paper, msg)
-            else:
-                next_q = paper.completed_question(question.id)
-                return show_question(request, next_q, paper)
+            next_q = paper.completed_question(question.id)
+            return show_question(request, next_q, paper)
     else:
         return show_question(request, question, paper)
 
@@ -576,11 +561,13 @@ def validate_answer(user, user_answer, question, json_data=None):
             expected_answer = question.get_test_case(correct=True).options
             if user_answer.strip() == expected_answer.strip():
                 correct = True
+                result['error'] = 'Correct answer'
         elif question.type == 'mcc':
             expected_answers = []
             for opt in question.get_test_cases(correct=True):
                 expected_answers.append(opt.options)
             if set(user_answer) == set(expected_answers):
+                result['error'] = 'Correct answer'
                 correct = True
         elif question.type == 'code':
             user_dir = get_user_dir(user)
@@ -681,10 +668,15 @@ def courses(request):
     ci = RequestContext(request)
     if not is_moderator(user):
         raise Http404('You are not allowed to view this page')
-    demo_user = User.objects.get(username="demo_user")
+    try:
+        demo_user = User.objects.get(username="demo_user")
+    except User.DoesNotExist:
+        demo_user = None
     courses = Course.objects.filter(Q(creator=user) | Q(creator=demo_user),
                                     is_trial=False)
-    return my_render_to_response('yaksh/courses.html', {'courses': courses},
+    allotted_courses = Course.objects.filter(teachers=user, is_trial=False)
+    context = {'courses': courses, "allotted_courses": allotted_courses}
+    return my_render_to_response('yaksh/courses.html', context,
                                  context_instance=ci)
 
 
@@ -891,8 +883,9 @@ def show_all_questions(request):
                 questions_file = request.FILES['file']
                 file_name = questions_file.name.split('.')
                 if file_name[-1] == "zip":
+                    ques = Question()
                     extract_files(questions_file)
-                    read_json("questions_dump.json", user)
+                    ques.read_json("questions_dump.json", user)
                 else:
                     message = "Please Upload a ZIP file"
                     context['message'] = message
@@ -1186,25 +1179,24 @@ def search_teacher(request, course_id):
         raise Http404('You are not allowed to view this page!')
 
     context = {}
-    course = get_object_or_404(Course, creator=user, pk=course_id)
+    course = get_object_or_404(Course, pk=course_id)
     context['course'] = course
 
+    if user != course.creator and user not in course.teachers.all():
+       raise Http404('You are not allowed to view this page!')
+
     if request.method == 'POST':
         u_name = request.POST.get('uname')
-        if len(u_name) == 0:
-            return my_render_to_response('yaksh/addteacher.html', context,
-                                        context_instance=ci)
-        else:
+        if not len(u_name) == 0:
             teachers = User.objects.filter(Q(username__icontains=u_name)|
                 Q(first_name__icontains=u_name)|Q(last_name__icontains=u_name)|
-                Q(email__icontains=u_name)).exclude(Q(id=user.id)|Q(is_superuser=1))
+                Q(email__icontains=u_name)).exclude(Q(id=user.id)|Q(is_superuser=1)|
+                                                    Q(id=course.creator.id))
             context['success'] = True
             context['teachers'] = teachers
-            return my_render_to_response('yaksh/addteacher.html', context,
-                                        context_instance=ci)
-    else:
-        return my_render_to_response('yaksh/addteacher.html', context,
-                                    context_instance=ci)
+                                        
+    return my_render_to_response('yaksh/addteacher.html', context,
+                                 context_instance=ci)
 
 
 @login_required
@@ -1218,8 +1210,11 @@ def add_teacher(request, course_id):
         raise Http404('You are not allowed to view this page!')
 
     context = {}
-    course = get_object_or_404(Course, creator=user, pk=course_id)
-    context['course'] = course
+    course = get_object_or_404(Course, pk=course_id)
+    if user == course.creator or user in course.teachers.all():
+        context['course'] = course
+    else:
+        raise Http404('You are not allowed to view this page!')
 
     if request.method == 'POST':
         teacher_ids = request.POST.getlist('check')
@@ -1228,36 +1223,21 @@ def add_teacher(request, course_id):
         course.add_teachers(*teachers)
         context['status'] = True
         context['teachers_added'] = teachers
-        return my_render_to_response('yaksh/addteacher.html', context,
-                                    context_instance=ci)
-    else:
-        return my_render_to_response('yaksh/addteacher.html', context,
+        
+    return my_render_to_response('yaksh/addteacher.html', context,
                                     context_instance=ci)
 
 
-@login_required
-def allotted_courses(request):
-    """  show courses allotted to a user """
-
-    user = request.user
-    ci = RequestContext(request)
-    if not is_moderator(user):
-        raise Http404('You are not allowed to view this page!')
-
-    courses = Course.objects.filter(teachers=user)
-    return my_render_to_response('yaksh/courses.html', {'courses': courses},
-                                        context_instance=ci)
-
 
 @login_required
 def remove_teachers(request, course_id):
     """  remove user from a course """
  
     user = request.user
-    if not is_moderator(user):
+    course = get_object_or_404(Course, pk=course_id)
+    if not is_moderator(user) and (user != course.creator and user not in course.teachers.all()):
         raise Http404('You are not allowed to view this page!')
 
-    course = get_object_or_404(Course, creator=user, pk=course_id)
     if request.method == "POST":
         teacher_ids = request.POST.getlist('remove')
         teachers = User.objects.filter(id__in=teacher_ids)